Temperature measuring apparatus



April 1942- P. 1.. STAPLETON 2,279,846

TEMPERATURE MEASURING APPARATUS Filed Jan. 27, 1940 s Sheets-Shee 1 L' Inventor-r Patrick L.. Stapleton,

His ttor-ne g.

p l 14, 1942 P. L. STAPLETON 2,279,846

TEMPERATURE MEASURING APPARATUS Filed Jan. 27, 1940 5 Sheets-Sheet 2 Invent or: Patrick L. Stap'leton,

His Attorney.

April 14, 1942. P. L. STAPLEYTON 2,279,846

TEMPERATURE MEASURING APPARATUS Filed Jan. 27, 1940 3 Sheets-Sheet 5 Inventor" Patrick L Stapleton,

l-iis Att or-ney claims.

Patented Apr-.14, 1942 UNITED STATES PATENT OFFICE TEMPERATURE MEASURING APPARATUS Patrick L. Stapleton, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application January 27, Serial No. 315,989

9 Claims.

'a compact, portable, temperature measuring device in which the temperature responsive element and an electrical indicating instrument are embodied in a single unit and provided with means for maintaining the temperature responsive instrument close to or in contact with an object, the temperature of which is to be measured.

It is another object of my invention to provide a simple arrangement for maintaining a thermocouple element close to or in contact with a plane or curved surface of a stationary or relatively movable ferrous metallic body, the temperature of which is to be measured.

In accordance with my invention in its preferred form, I provide a temperature measuring device comprising a thermocouple element which is secured to a permanent magnet composed of a material having the ability to retain its magnetic properties at temperatures as high as approximately 1000 F. The permanent magnet is employed to hold, the thermocouple or temperature sensitive device close to or against ferrous metallic bodies undergoing heat treatment. I provide a suitable keeper element which may be operated manually or automatically to aid in conserving the available magnetic energy of the permanent magnet when the device is not being used for measuring temperatures.

The temperature measuring device of my invention may be provided with an electrical measuring instrument which is secured directly to the permanent magnet element or the electrical instrument which indicates the temperature may be connected to the thermocouple element through a microphone type plug and connector arrangement or other suitable conducting means. Arrangements of the foregoing character are suitable for measuring the temperature of either statonary or relatively movable bodies.

The novel features which are characteristic of r y invention are po nted out in the appended My invention, however, will be understood more readily from reference to thefollowing specification when considered in connection with the accompanying drawings in which Figs. 1 to 4 illustrate severalviews of a temperature measuring device constructed in accordance with my invention and provided with a manual keeper element; Figs. 5 to 8 'show a modification in which a single automatic keeper is provided for preserving the strength of the permanent magnet element; Figs. 9 and 10 represent a further modification showing the use of a double automatic keeper arrangement; Figs. 11 to 13 illustrate modifications showing different types of thermocouple elements secured to the permanent magnet; Fig. 14 illustrates a temperature measuring device arranged in accordance with my invention for measuring the surface temperature of a rotating body; Figs. 15 and 16 illustrate an arrangement incorporating the permanent magnet, the thermocouple element and an electrical measuring instrument, as a unitary device, and adapted particularly for measuring the temperature of a stationary or relatively movable plane or curved surface; and Fig. 17 is a partial plan view of the bottom side of the arrangements illustrated in Figs. 15 and 16.

Referring to Figs. 1 to 4 of the drawings, I have illustrated a permanent magnet'element 80 of horseshoe shape to which is secured a temperature sensitive element, such as a thermocouple I l, the output terminals of which are shown connected to a temperature indicating device I2. In Fig. 2 the device is shown in position for measuring the surface temperature of a ferrous metallic body l3.

In constructing the permanent magnet element I0, I prefer to employ magneticmaterials which are characterized by a high coercive force in order that the magnet may be highly resistant to various de-magnetizing influences. I further desire to have a magnetic material which is capable of retaining its magnetic properties even at elevated temperatures. While I do not intend that my invention shall be limited to the employment of a particular magnetic material, I have found thathighly satisfactory results may be obtained by the employment of permanent magnet alloys containing iron, nickel, and aluminum as the basic or essential ingredients: These magnets may be prepared in accordance with the teachings of United States Patents Nos. 1,947,274 and 1.968.569 to Wm'. E. 'Ruder, and 2,027,994 to 2,028,000, inclusive, to Tokuschichi Mishima. Or,

if desired, the magnet may be formed by a sintering process as disclosed in United States Patent 2,192,743, datedM arch 5, 1940, or Goodwin n.

ment illustrated, comprises a thin flexible sensitive member consisting of two thermocouple strips of dissimilar metals preferably joined together end to end by a welding or soldering process to produce a thermocouple junction Ila. I provide means for securing the thermocouple element in supported relation to the permanent magnet element it. In accordance with the illustrated embodiment, this'means comprises substantially a U-shaped clamp member 94 which is adapted to be positioned over the permanent magnet element and secured thereto by any suitable means such as a bolt member II. I position the leads l8 and I1 leading from the thermocouple junction in clamped relation between the outer side portions I8 of the member l4 and lug members l9 and 20, respectively. The lug members are preferably provided with inturned lower end portions 2| for maintaining the thermocouple wires flrmly in position with respectto the lower portion of the supporting member I4. I may provide a spring clip member 22 for applying a pressure along the lug members I! and to hold the thermocouple leads firmly in position. The bolt member I6 is preferably threaded and provided with a nut 23 ateach end to maintain the tion.

I prefer to compose the member l4, the bolt or stud II, the nuts 23 and the lugs i9 and 20 of a non-magnetic material, such as aluminum. In the case of the clamp l4 and the lugs l9 and 20, I employ aluminum which has been anodized. By the term "anodized I mean that these members have a protective insulating film or coat of aluminum oxide on their surfaces which keeps the thermocouple from short circuiting. This coating is very effective-a an insulating medium for the small millivoltages generated within the temperature ranges of devices of this character. The leads l6. and I! from the thermocouple element may be joined at 24 and 25 by other conducting leads 28 and 21 for connecting the thermocouple element in circuit with a suitable temperature indicating device l2. 'The conductors 26 and 21 leading to the temperature indicating device l2 are preferably arranged in the Parts in fixed rela- 'form of a cable 28 having a heat-resistant, insulated covering, composed of a suitable material such as asbestos. I preferably employ a readily detachable connector 29, comprising a plug 29a. and contact portions 30 and 3| in the circuit between the temperature indicating device l2 and the leads 28 and 21 to provide convenient means for removing the instrument from and inserting it in the circuit with the thermocouple. I may likewise employ a suitable armor arrangement .32 about the. cable 28 at the neck portion 33 of the supporting member 14.

I provide means for preserving as much of the magnetic energy of the magnet I0 as possible when it is not in use. In accordance with the arrangement illustrated, this comprises a pluan arm or lever 35 for pivotal movement about a pivot pin 36 supported by a pair of ears or oiiset portions 21 of the lug or clamping members I9 and 20. With this construction the parts 34, 34 which form the keeper element may be moved over the pole faces 39 as shown in Figs. 1, 3 and 4 or they may be moved off the pole faces as shown in Fig. 2. A resilient member such as a spring 28 provides means for moving the keeper elements outwardly to a position where they are substantially ineifective as keepers and for holding the armature elements outwardly in retracted position against. the force of gravity, as illustrated in Fig. 2.

In operation, the keeper or armature elements 34, which occupy the position shown in Figs. 1, 3

and 4 when the device is not in use, are removed from the pole faces 39 of the magnet by exerting a force against the opposite end portions 40 of the pivotally mounted arms 35. Once they are removed from the .direct influence of the attractive force at the pole faces 39, the armatures 34 will occupy the position shown .in Fig. 2 due to the force exerted by the spring 39. The permanent magnet III is then positioned with its pole faces 39 in surface engagement with the object I3 whose temperature is to be measured. By

means of such an arrangement, the thermocouple surface contact pressure is maintained at a uniform value and true temperatures will be indicated whether or not the magnet I0 is at the same temperature as the work i3.

In Figs. 5 to 8 I have illustrated a modified arporting member or clamp 41 which, as illustrated in the drawings, is adapted to slide over the end portions 39 of the magnet and is positioned about the central portion by means of a stud or bolt ii. I may make the lug members 42 of slightly different construction from the lug members l9 and 20 already described inasmuch as a diflerent arrangement is employed for supporting the keeper element. The lug members 42 in this instance are likewise provided with inturned end portions, such as 43, each of which extends .through a transverse opening 44 in the supporting member 4|.

A single keeper element 45 of suitable magnetic material is supported by an arm or lever 48 which is pivotally supported by a pin 4! enga-ging the lower section or lug portions of the clamp 4|. 1 may provide an adjustable stud or screw 48 in threaded engagement with the lower por- 45 is suflicient to overcome the adjustable spring rality of magnetic or soft iron armatures or keeper elements 34 each of which is suspended on pressure and the keeper element is attracted to the poles by the magnetic flux of the magnet. With proper adjustment the keeper remains against the smooth side portions SI of the magnet poles as illustrated in Fig. 6 until the magnet is placed with its pole faces 39 in contact with the work 8 Or body whose temperature is to be measured. when this takes place a portion of having a cut-away portion 65 for transmitting the magnetic flux in the keeper 55 is diverted to the force of a helical spring to to position the the body It and this allows the spring 50 to push thermocouple element 1 I in thermal relationship the keeper outwardly and away from the magnet, with the surface of the body whose temperature as illustrated in Fig. 7, thus increasing the relucis to bemeasured, as, for example, at a minimum tance of the magnetic path through the keeper distance from or in engagement with the surface so that most of the flux then passes through the of the curved member 62. By virtue of the cutbody it. An adJustable stop member 52 ,of a away portion 65, the flexible thermocouple elesuitable material such as brass,' is provided to 'ment H is made to conform to the curved surface limit the outward travel oi the keeper so that in those cases where it is desired to maintain when the magnet is removed from the work, the actual surface contact between the member 62 magnetic flux pulls the keeper back in place and the temperature responsive element. 1 proagalnst the sides of the poles. 1 vide the permanent magnet ID with a keeper ele- The various parts just described are constructed ment 8'! which will presently be described in more preferably of the same materials as the corredetail. sponding elements described in connection with The reference character 88 designates a wall of Figs. 1 to 4. a V a furnace inside of which might be placed a body In Figs. 9 and 10 I have illustrated an arrangesuch as the rotating "shaft 62 which is being subment which embodies the use of two-automati jected to heat treatment. I have illustrated a cally controlled keeper elements to aid in retainmember in the form of a rigid metal strip 69 in! the magnetism of the permanent magnet. which extends through an opening Ill in the fur- In this arrangement, a clamp or supporting memnace and which has a slotted portion II for allowber 55 which i likewise adapted t li v th ing the thermocouple element l I to be positioned ends 39 of the magnet is'positionedabout the adjacent the surface of the body 62. The inner central portion of the magnet in and clam ed end of the member i9 is constructed of magnetic firmly to the magnet by means of a stud or bolt materiel to Pr de 8 medium for holding the ii. The depending portion 49 as shown in Fig, 6 magnet III in position about. the slot II. The is dispensed with and pair of arms 58, 5B ar leads l6 and H of the thermocouple element ll pivotally mounted bout pins 51 n m ch t may be connected to a measuring instrument same manner as the arm 46 of Fig. 6, and sup u h the cable 28. ported from the clamp 56. A pair of armature The operation of the device is believed to be elements or keepers 58, 5a are held to the side ear. T e s p e e 9 which is pported of the magnet poles as indicated against the force in y convenient ner maintains the p exerted by the springs 59. When the magnet i nent magnet 60 in the position shown to hold the positioned against magnetic material such as the thermocouple e e t II n Contact with or a work, both keeper elements are forced outwardly minimum dlstallee from the Surface 5 e d it as already described in connection with Figs. 6 will be app at un er such conditions to a the keeper element is automatically movable outin Figs. 11 and 12 I have shown a modified wardly and away from the po es of he a net. form of thermocouple element secured to the The details of the thermocouple e hown in permanent magnet it. In this arrangement, I e larged form in Fi secure each of the thermocouple wires 86 and H In F 5 and 16 I have shown a modified of dissimilar metals to the magnet by means of arrangement in which 8 temperature indicating copper m tal Spray prgcess, h wires are device 'lh'is fixedly mounted on the permanent then. fixed to an anodized aluminum supporting 4,5 magnet element A suita le a an ement member at which is adapted to slide over the which I ay p y for s u the d atin ends at of the magnet it and which may be fasdevice to e et co p es a plate M prefl'ened firmly to the magnet by means of t d erably composed of non-magnetic material such M which engages the inner surface of the HS bless and which has two depending members magnet i m llh which are shown clamped about the magnet In Fig. 13 I have illustrated a modification of by means of a pin it. The measurin in truthe arrangement shown in Figs. 11 and i2 wherement 15 P d with & P f r inals 1 for in the thermocouple wires to and ll! are peened Connecting o the op ends 18 and I9 of a therin the surfaceof the outer edge of the magnet moeouple element 80. The thermocoup e eleand in each of the pole faces til, respectively. ment ill this instance is P o ded with means Th supporting membe no i lik i held firmly similar to that described in connection with Fig. in position to the magnet by means of a stud ti. 14 for pi n j a i h pressure to the thermo- It will be appreciated that in constructing the p e e me t for maintaining it in firm conclamp at I may employ a t ri l imil m that tact with or close to the surface of a magnetic described in connection with the clamping membo y ill the temperature of which is to be measb r it f Fig, 1, ured. In order to adapt the arrangement to the In Fig, 14 I have illustrated an arrangement measurement of the'temperature of relatively which is particularly suitable for measuring the movable Surfaces f bodies such as 3| 1 e P temperature of moving plane or curved surfacw. lvlded anti-friction means reducing the fr e- The particular illustration shows the device being 5 tiollel Contact between t agne and the movused for measuring the temperature of a rotating ins surface. In the arran m n illu rated. this shaft or cylinder 62 while undergoing heat treatmp s a plurality of freely mova le alls t2 ment but is also well adapted to the measurement f Steel 01 other suitable material mounted in a of the temperature of the rolls in a paper calenrecess 83 formed in each pole face of the magnet dering machine, and the like. In the illustrated II!- In the arrangement illustrated a p le Pi c embodiment, the permanent magnet element in at of relatively permeable material, such as soft supports the wires It and H of a thermocouple ir nais joined to each of the magne p with element from a member 68 which is clam ed this arrangement the recesses t3 may more easily about the magnet. I provided a member 84 combe formed and also the flux relations of the mag- 1, posed of a suitable material such as asbestos and 75, net will be improved. This arrangement permits the body 8| to move freely relative to the magnet 10 and the temperature sensitive element 80 is held in firm contact with the surface while the temperature is being measured. The temperature measuring device may be prevented from moving with the body 8| by applying a small restraining force either manually or by means of a flexible linkage system such as 85 secured at one end to the magnet and at the other end to a fixed member. It will be appreciated that this type of support including the balls 82 may also be employed in connection with the arrangement of Fig. 14 thereby making it possible to dispense with the member 69.

An automatically operated keeper element 61, of the character illustrated in connection with Fig.14, is also provided with the arrangement of Fig. 15. This device, comprising a magnetic armature is ad'apted' for movement toward and away from the poles of the magnet l0 and carries the magnetic flux of the magnet when the latter. is not being employed to maintain the temstillother useful 'fields of application.- As indi-' perature sensitive element in the measuring position. In accordance with the'illustrated arrangement shown in partial section in 16,

I secure a hollow member 89, in the form of acylinder; to opposite edges of the magnet I0 and adjacent the magnet poles by welding or brazing the parts together as shown at 81. Loosely positioned for axial movement within the member 86 is the cylindrical portion 88 of a member 89. The member 89 is also provided with an internally threaded stem portion 90; which engages an adjustable stud or pin 9|. A helical spring 92 is positioned between an adjustable disc or plug 93 and the member 89 and thus supplies a biasing force tending to push the member 99 away from the magnet. By properly positioning the plug 93 within the shell 98 the force exerted by the spring may be adjusted to the desired value, and

'. magnetic material such as brass, in order that the fiux from the magnet may be forced directly from the poles 8| through the magnetic armature 94. It will'be observed that the armature 94, even when in the attracted position, is separated from each of the magnet poles by the thin,

in order to avoid local heating action due to friction.

Ihave thus provided a simple, convenient, durable, and compact temperature measuring device which may be found quite useful in many temperature measuring applications where the range in temperature does not greatly exceed 1000 F. A device of this character has been found 'to be particularly suited to the measurement of the,

temperature of materials in the process of manufacture. Also, it is well adapted to making temperature measurements in connection with the welding of turbine bucket blades to alloys in which the thermal characteristics are critical. Furthermore, temperature measurements in connection with mica forming molds, shrink fits, platens in forming presses and the like, present cated in connection with the description of oer.- tain embodiments of my invention, apparatus of -this character is also adapted to the measurement of temperatures 'of' moving bodies having plane orcurved surfaces.

In accordance with the provisions ofthe patent statutes, I have described the principle of operation of my invention together with the apps.- ratus which I now consider to represent the best embodiments thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention maybe'carried out by other means.

What I claim as new and desire to secure by Letters Patent'of the United States is:

1. In a temperature measuring device, a permanent magnet element, a thermocouple element, means for securing said thermocouple element to said permanent magnet, whereby the attractivefcrce of said magnet may be employed for positioning said thermocouple adjacenta body the temperature of which is to be measured, and

- means for biasing said thermocouple element into thermal relationship with the surface of the body.

2. In a device for measuring the-temperature of a moving body of magnetic material, a permanent magnet element, a temperature-sensitive element, means for securing said temperature sensitive element to said permanent magnet portion 96 of the member 99. By having this non-magnetic spacer element between the armature and the poles, the automatic operation of the armature is improved. When the magnet is positioned in operative relation with the surface 8|, the force of the spring 92 causes the keeper element 61 to be moved outwardly from the magnet and the head portion of the pin 9| acts as a stop to limit this outward movement.

. In the foregoing arrangements the thermo-;

couple element is always maintained in the same position adjacent the surface of the hot body the temperature of which is to be measured. The term adjacent as employed in this specification is intended to bedescriptiv'e of those situations where the thermocouple element is positioned element for maintaining the magnetic properties of said magnetwhen said device is not in use for measuring temperature, means for biasing said keeper element to a position in which the keeper element is substantially ineffective whereby said keeper element is automatically retractable from said magnet 'when'the poles of said magnet are positioned in operative relation adjacent said magnetic body and automatically operable ,to carry the flux of said magnet when said magnet is removed from said body.

4.'In a device for measuring temperature, a-

flexible temperature sensitive element, a permanent magnet, means for securing said temperature sensitive element to said permanent magnet whereby the attractive force of said magnet may be employed to maintain said temperature sensimagnet, a temperature responsive element, means for securing said temperature responsive element to said permanent magnet whereby the attractive force of said magnet may be employed for positioning said element in predetermined relation adjacent said body whose temperature is to be measured, and means carried by said securing means and disposed adjacent said magnet for movement into a position adjacent thereto for conserving the flux in said magnet when said instrument is in the inoperative position.

6. In a temperature measuring device, a permanent magnet element, a thermocouple element having relatively flexible leads joined to form a thermocouple junction, means for securing said thermocouple element to said permanent magnet, whereby the attractive force of said magnet may be employed for positioning said thermocouple adjacent a body the temperature of which is to be measured, means for biasing the thermocouple junction of said thermocouple into contact with the surface of said body, and means interposed between said biasing, means and said means for transmitting the biasing force to said junction 7. In a temperature measuring device, a permanent magnet element, a thermocouple element having relatively flexible leads joined to form a thermocouple junction, means for securing said thermocouple element to said permanent magnet whereby the attractive force of said magnet may be employed for positioning said thermocouple adjacent a body the temperature of which is to be measured, means for biasing the thermocouple junction of said thermocouple into contact with the surface of said body, and means interposed between said biasing means and said means for transmitting the biasing force to said junction and leads, said transmitting means being shaped to cause said junction and said leads to assume the shape of said body.

8. In a temperature measuring device, a permanent magnet element, a thermocouple element having relatively flexible leads, means for securing said thermocouple element to said permanent magnet whereby the attractive force of said magnet may be employed for positioning said thermocouple adjacent a body the temperature of which is to be measured, means for biasing said leads into contact with the surface of said body, and means interposed between said biasing means and said means for transmitting the biasing force to said leads, a portion of said transmitting means being cut away to permit said leads to conform to the shape of the surface of said body.

9. In a temperature measuring device, a temperature sensitive element, means including a permanent magnet for maintaining said temperature sensitive element in a predetermined position relative to a magnetic body the temperature of which is to be measured and a keeper element for maintaining the magnetic properties of said magnet when said device is not in use for measuring temperature, spring means for biasing said keeper element to a position in which said element is substantially ineffective, said spring means being of such strength that when the permanent magnet is out of.contact' with said body the flux threading the keeper will overcome the spring pressure so that said keeper is attracted to said magnet but when said magnet is adjacent said body the flux is diverted from said keeper whereby said keeper is moved outwardly to the position in which the keeper is substantially ineffective.

PATRICK L. STAPLETON. 

